Information transmission method and device

ABSTRACT

Embodiments of the present invention provide an information transmission method and device. The method includes: reporting, by a UE, a CQI value to an eNB; receiving, by the UE, an MCS value sent by the eNB, where the MCS value is determined by the eNB according to the CQI value; and receiving, by the UE, PDSCH data according to the MCS value, where the CQI value and the MCS value are determined according to a second set of tables, where a modulation scheme that can be supported by the second set of tables is higher than 64QAM. The embodiments of the present invention can improve system performance and reduce waste of feedback resources.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/158,509, filed on Oct. 12, 2018, which is a continuation of U.S.patent application Ser. No. 15/854,641, filed on Dec. 26, 2017, now U.S.Pat. No. 10,103,838, which is a continuation of U.S. patent applicationSer. No. 15/271,044, filed on Sep. 20, 2016, now U.S. Pat. No.9,871,618, which is a continuation of U.S. patent application Ser. No.14/474,532, filed on Sep. 2, 2014, now U.S. Pat. No. 9,479,287, which isa continuation of International Application No. PCT/CN2013/071684, filedon Feb. 20, 2013, which claims priority to Chinese Patent ApplicationNo. 201210054842.6, filed on Mar. 2, 2012. All of the afore-mentionedpatent applications are hereby incorporated by reference in theirentireties.

TECHNICAL FIELD

The present invention relates to mobile communications technologies, andin particular, to an information transmission method and device.

BACKGROUND

Currently, an auto negotiation process of a physical downlink sharedchannel (Physical Downlink Shared Channel, PDSCH) in a Long TermEvolution (Long Term Evolution, LTE) system is: A user equipment (UserEquipment, UE) estimates channel information that is used to measurechannel state information (Channel State Information, CSI); by using theestimated channel information, the UN calculates a signal tointerference plus noise ratio (Signal to Interference plus Noise Ratio,SINR) based on an optimal rank indication (Rank Indication, RI) and/or aprecoding matrix indication (Precoding Matrix Indication, PMI); the UEquantizes the calculated SINR into a 4-bit channel quality indicator(Channel Quality indicator, CQI); the UE reports the CQI value to anevolved NodeB (evolution NodeB, eNB); the eNB allocates a modulation andcoding scheme (Modulation. and Coding Scheme, MCS) to the UN accordingto the CQI value reported by the UN and network conditions, where theMCS is used to indicate the modulation and coding scheme currently usedby the PDSCH; and the UN receives PDSCH data according to the MCS. Inthe process of quantizing the SINR into the CQI, a main interval of theSINR is (−7 dB, 19.488 dB), and SINRs outside the interval are processedin a saturation manner.

In a hotspot scenario such as a relay (Relay) or LTE hotspotimprovements (LTE Hotspot Improvements, LTE-Hi) scenario, all SINRvalues obtained by the UE are large. For example, under certainconditions, almost 50% of SINR values of the UE are greater than, 20 dB.However, because the SINR values greater than a maximum value of themain interval are processed in a saturation manner in the process ofquantizing the SINR into the CQI, and an index of a CQI corresponding toan SINR in the saturation manner is 15, the UE at most can select only amodulation and coding scheme corresponding to the CQI whose index is 15,which restricts a terminal from selecting a higher modulation and codingscheme and affects system performance.

SUMMARY

Embodiments of the present invention provide an information transmissionmethod and device to solve a problem that system performance is lowerthan expected in the prior art.

An embodiment of the present invention provides an informationtransmission method, including:

reporting, by a UE, a CQI value to an eNB;

receiving, by the UE, an MCS value sent by the eNB, where the MCS valueis determined by the eNB according to the CQI value; and

receiving, by the UE, PDSCH data according to the MCS value,

where the CQI value and the MCS value are determined according to asecond set of tables, where a modulation scheme that can be supported bythe second set of tables is higher than 64QAM.

An embodiment of the present invention provides an informationtransmission device, including:

a first sending module, configured to report a CQI value to an eNB;

first receiving module, configured to receive an MCS value sent by theeNB, where the MCS value is determined by the eNB according to the CQIvalue; and

a second receiving module, configured to receive PDSCH data according tothe MCS value,

where the CQI value and the MCS value are determined according to asecond set of tables, where a modulation scheme that can be supported bythe second set of tables is higher than 64QAM.

From the foregoing technical solution, it can be learned that in theembodiments of the present invention, a set of CQI and MCS tables isreset so that the CQI and the MCS can support modulation schemes higherthan 64QAM, therefore implementing support for higher modulationschemes, meeting requirements in a hotspot scenario and improving systemperformance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a schematic flowchart of an embodiment of an informationtransmission method according to the present invention;

FIG. 2 is a schematic flowchart of another embodiment of an informationtransmission method according to the present invention;

FIG. 3 is a curve of relationships between spectral efficiency and SINRsin different modulation schemes according to the present invention;

FIG. 4 is a schematic structural diagram of an embodiment of aninformation transmission device according to the present invention;

FIG. 5 is a schematic structural diagram of another embodiment of aninformation transmission device according to the present invention; and

FIG. 6 is a schematic structural diagram of another embodiment of aninformation transmission device according to the present invention.

DETAILED DESCRIPTION

FIG. 1 is a schematic flowchart of an embodiment of an informationtransmission method according to the present invention, including:

Step 11: A UE reports a CQI value to an eNB.

Step 12: The UE receives an MCS value sent by the eNB, where the MCSvalue is determined by the eNB according to the CQI value.

Step 13: The UE receives PDSCH data according to the MCS value,

where the CQI value and the MCS value are determined according to asecond set of tables, where a modulation scheme that can be supported bythe second set of tables is higher than 64QAM.

For a better understanding of the present invention, the following firstdescribes a CQI table and an MCS table in an existing protocol. Table 1is a CQI table in the existing protocol, and Table 2 is an MCS table inthe existing protocol.

TABLE 1 Modulation Spectral CQI index scheme Code rate × 1024 efficiency(CQI index) (modulation) (code rate × 1024) (efficiency) 0 Out of range(out of range) 1 QPSK 78 0.1523 2 QPSK 120 0.2344 3 QPSK 193 0.3770 4QPSK 308 0.6016 5 QPSK 449 0.8770 6 QPSK 602 1.1758 7 16 QAM 378 1.47668 16 QAM 490 1.9141 9 16 QAM 616 2.4063 10 64 QAM 466 2.7305 11 64 QAM567 3.3223 12 64 QAM 666 3.9023 13 64 QAM 772 4.5234 14 64 QAM 8735.1152 15 64 QAM 948 5.5547

TABLE 2 MSC Modulation Transport block size index order (transport blocksize, (MCS (modulation TBS) index index) order) (TBS index) I_(MCS)Q_(m) I_(TBS) 0 2 0 1 2 1 2 2 2 3 2 3 4 2 4 5 2 5 6 2 6 7 2 7 8 2 8 9 29 10 4 9 11 4 10 12 4 11 13 4 12 14 4 13 15 4 14 16 4 15 17 6 15 18 6 1619 6 17 20 6 18 21 6 19 22 6 20 23 6 21 24 6 22 25 6 23 26 6 24 27 6 2528 6 26 29 2 Reserved (reserved) 30 4 31 6

The numbers 2, 4 and 6 in the modulation orders in the foregoing MCSrespectively denote the following modulation schemes: quadrature phaseshift keying (Quadrature Phase Shift Keying, QPSK), 16 quadratureamplitude modulation. (Quadrature Amplitude Modulation, QAM), and 64QAM.

It can be seen from Table 1 and Table 2 that the modulation schemes thatcan be supported by the CQI/MCS in the existing protocol are QPSK,16QAM, and 64QAM, and the modulation scheme of the highest order is64QAM.

In a hotspot scenario, an SINR is mostly high, and can sufficientlysupport a modulation scheme higher than 64QAM. However, according to anexisting protocol manner, the highest supported modulation scheme isonly 64QAM, which affects system performance.

In this embodiment of the present invention, requirements in the hotspotscenario are considered and a set of CQI/MCS tables is redesigned. Todistinguish from the existing protocol, the existing CQI/MCS tables maybe referred to as a first set of tables, and the tables redesigned inthis embodiment of the present invention may be referred to as a secondset of tables. The second set of tables in this embodiment of thepresent invention supports modulation schemes of higher orders, andsupport for 256QAM is used as an example in this embodiment of thepresent invention. Surely, if modulation schemes of higher order need tobe supported, modulation schemes of even higher orders such as 1024QAMmay be supported.

In specific implementation, a CQI table of a same size as that of anexisting CQI table may be used. In this case, values of a modulationscheme, a code rate and spectral efficiency corresponding to each CQIindex in the CQI table need to be redesigned; or, the number of bits ofthe CQI may also be extended, for example, the CQI in the prior art is 4bits, and the CQI in this embodiment of the present invention may bedesigned as 5 bits, and therefore, there are 16 additional indexes morethan the indexes of the existing CQI, and the additional part is used todenote 256QAM. For specific implementation, refer to subsequentembodiments.

FIG. 2 is a schematic flowchart of another embodiment of an informationtransmission method according to the present invention, including:

Step 21: A UE sends control signaling to an eNB, where the controlsignaling is used to indicate that the OF supports a second set oftables.

The UE may use a feature group indicator (feature Group Indicators, FGI)bit or another radio resource control (Radio Resource Control, RRC)command to notify the eNS that the UE supports the second set of tables.

Step 22: The eNB sends control signaling to the UE, where the controlsignaling is used to indicate use of the table.

After determining that the UE can support the second set of tables, theeNB may decide whether to use a first set of tables or the second set oftables according to actual network conditions.

For example, the eNB may determine to use the second set of tables ifdetermining that the existing channel conditions are good, andspecifically, if a reference signal received power (Reference SignalReceived Power, RSRP) or reference signal received quality (ReferenceSignal Received Quality, RSRQ) that is obtained by means of measurementis greater than a set value. Alternatively, the eNB may determine to usethe second set of tables if all CQI orders reported by the UE andreceived by the eNB in a set time are higher than a set order and datais continuously and correctly received. For example, if all CQI ordersreported by the UE and received by the eNB in a set time T are 64QAM anddata is continuously and correctly received, the eNB may determine thata modulation scheme of a higher order can be used, and therefore,determine to use the second set of tables.

If the eNB determines to use the second set of tables, control signalingthat is used to indicate use of the second set of tables is specificallysent, and this case is used as an example in this embodiment. It can beunderstood that, when the eNB determines to use the first set of tables,after the eNB sends to the UK control signaling that is used to indicateuse of the first set of tables, execution may be implemented accordingto the prior art.

Step 23: The UE determines a CQI value according to a second set offormats, and sends the CQI value to the eNB.

Step 24: The eNB determines an MCS value according to the second set offormats, and sends the MCS value to the UE.

Step 25: The UK receives PDSCH data according to the MCS value.

The CQI table in the second set of tables may be shown in Table 3, andthe MCS table in the second set of tables may be shown in Table 4 orTable 5.

TABLE 3 CQI index Modulation Spectral (CQI scheme Code rate × 1024efficiency index) (modulation) (code rate × 1024) (efficiency) 0 Out ofrange (out of range) 1 QPSK 75 0.1467 2 QPSK 294 0.5733 3 QPSK 7241.4133 4  16 QAM 423 1.6533 5  16 QAM 587 2.2933 6  16 QAM 764 2.9867 7 64 QAM 573 3.3600 8  64 QAM 655 3.8400 9  64 QAM 728 4.2667 10  64 QAM801 4.6933 11  64 QAM 874 5.1200 12 256 QAM 696 5.4400 13 256 QAM 7786.0800 14 256 QAM 860 6.7200 15 256 QAM 942 7.3600

TABLE 4 Transport block size MSC index Modulation order (transport blocksize, TBS) (MCS index) (modulation order) index (TBS index) I_(MCS) Q_(m) I_(TBS) 0 2 0 1 2 1 2 2 2 3 2 3 4 2 4 5 4 5 6 4 6 7 4 7 8 4 8 9 4 910 4 10 11 6 11 12 6 12 13 6 13 14 6 14 15 6 15 16 6 16 17 6 17 18 6 1819 6 19 20 6 20 21 8 21 22 8 22 23 8 23 24 8 24 25 8 25 26 8 26 27 8 2728 2 Reserved (reserved) 29 4 30 6 31 8

TABLE 5 Transport block size (transport block MSC index Modulation ordersize, TBS) (MCS index) (modulation order) index (TBS index) I_(MCS) Q_(m) I_(TBS) 0 2 0 1 1 1 2 2 2 3 2 3 4 2 4 5 4 4 6 4 5 5 4 6 8 4 4 9 4 810 4 9 11 6 10 12 6 11 13 6 12 14 6 13 15 6 14 16 6 15 17 6 16 18 6 1719 6 18 20 6 19 21 8 19 22 8 20 23 8 21 24 8 22 25 8 23 26 8 24 27 8 2528 2 Reserved (reserved) 29 4 30 6 31 8

It can be seen from Table 3 that the CQI table in the second set oftables meets the following conditions:

(1) In any modulation scheme whose modulation order is higher thandifferences between two adjacent spectral efficiency values areapproximately equal, where a being approximately equal to b means thatan absolute value of a difference between a and b is less than a setvalue, where the set value may be 0.2.

For example, corresponding to 16QAM, spectral efficiency is 1.6533,2.2933, and 2.9867 respectively, and 2.2933-1.6533 is approximatelyequal to 2.9867-2.2933.

(2) A difference between spectral efficiency values that correspond totwo adjacent modulation schemes respectively is less than a differencebetween any two adjacent spectral efficiency values in a singlemodulation scheme in the two modulation schemes.

For example, corresponding to adjacent QPSK and 16QAM, the correspondingspectral efficiency is 1.4133 and 1.6533 respectively, and 1.6533-0.4133is less than 2.2933-1.6533, and is also less than 2.9867-2.2933.

Values in the CQI table that meets the foregoing condition may beobtained in the following manner:

determining a curve of relationships between an SINR and spectralefficiency each modulation scheme.

The spectral efficiency is defined as efficiency of correctlytransmitting bits of each modulation symbol, and may be denoted by:

${\eta = {\frac{M}{N} \times Q_{mod}}},$

where M is the number of transmitted bits, N is the number of bits afterencoding and rate matching are performed, mod is an modulation order,and the modulation order of QPSK is 2. The modulation order of 16QAM is4 . . . .

The design is based on scheduling of 4 RBs. The number N of bits thatcan be transmitted in the 4 RBs is obtained in the following manner:

One subframe (subframe) has 14 OFDM symbols, and one the OFEMs isreserved for a PDCCH, and the number of available OFDMs is 13.

One RB has 12 REs, and the number of valid REs in one RB of one subframeis 12×13=156.

4 RBs have 4×156=624 valid REs.

For QPSK modulation, the number (N) of encoded bits is 624×2=1248; and,for 16QAM, there are 624×4 bits, and so on. By now, N can be obtained.

The number (N) of original bits transmitted in the 4 RBs is obtained bysearching a table according to a IBS allowed by UP. For details, see thefollowing table:

i K ƒ₁ ƒ₂ 1 40 3 10 2 48 7 12 3 56 19 42 4 64 7 16 5 72 7 18 6 80 11 207 88 5 22 8 96 11 24 9 104 7 26 10 112 41 84 11 120 103 90 12 128 15 3213 136 9 34 14 144 17 108 15 152 9 38 16 160 21 120 17 168 101 84 18 17621 44 19 184 57 46 20 192 23 48 21 200 13 50 22 208 27 52 23 216 11 3624 224 27 56 25 232 85 58 26 240 29 60 27 248 33 62 28 256 15 32 29 26417 198 30 272 33 68 31 280 103 210 32 288 19 36 33 296 19 74 34 304 3776 35 312 19 78 36 320 21 120 37 328 21 82 38 336 115 84 39 344 193 8640 352 21 44 41 360 133 90 42 368 81 46 43 376 45 94 44 384 23 48 45 392243 98 46 400 151 40 47 408 155 102 48 416 25 52 49 424 51 106 50 432 4772 51 440 91 110 52 448 29 168 53 456 29 114 54 464 247 58 55 472 29 11856 480 89 180 57 488 91 122 58 496 157 62 59 504 55 84 60 512 31 64 61528 17 66 62 544 35 68 63 560 227 420 64 576 65 96 65 592 19 74 66 60837 76 67 624 41 234 68 640 39 80 69 656 185 82 70 672 43 252 71 688 2186 72 704 155 44 73 720 79 120 74 736 139 92 75 752 23 94 76 768 217 4877 784 25 98 78 800 17 80 79 816 127 102 80 832 25 52 81 848 239 106 82864 17 48 83 880 137 110 84 896 215 112 85 912 29 114 86 928 15 58 87944 147 118 88 960 29 60 89 976 59 122 90 992 65 124 91 1008 55 84 921024 31 64 93 1056 17 66 94 1088 171 204 95 1120 67 140 96 1152 35 72 971184 19 74 98 1216 39 76 99 1248 19 78 100 1280 199 240 101 1312 21 82102 1344 211 252 103 1376 21 86 104 1408 43 88 105 1440 149 60 106 147245 92 107 1504 49 846 108 1536 71 48 109 1568 13 28 110 1600 17 80 1111632 25 102 112 1664 183 104 113 1696 55 954 114 1728 127 96 115 1760 27110 116 1792 29 112 117 1824 2 114 118 1856 57 116 119 1888 45 354 1201920 31 120 121 1952 59 610 122 1984 185 124 123 2016 113 420 124 204831 64 125 2112 17 66 126 2176 171 136 127 2240 209 420 128 2304 253 216129 2368 367 444 130 2432 265 456 131 2496 181 468 132 2560 39 80 1332624 27 164 134 2688 127 504 135 2752 143 172 136 2816 43 88 137 2880 29300 138 2944 45 92 139 3008 157 188 140 3072 47 96 141 3136 13 28 1423200 111 240 143 3264 443 204 144 3328 51 104 145 3392 51 212 146 3456451 192 147 3520 257 220 148 3584 57 336 149 3648 313 228 150 3712 271232 151 3776 179 236 152 3840 331 120 153 3904 363 244 154 3968 375 248155 4032 127 168 156 4096 31 64 157 4160 33 130 158 4224 43 264 159 428833 134 160 4352 477 408 161 4416 35 138 162 4480 233 280 163 4544 357142 164 4608 337 480 165 4672 37 146 166 4736 71 444 167 4800 71 120 1684864 37 152 169 4928 39 462 170 4992 127 234 171 5056 39 158 172 5120 3980 173 5184 31 96 174 5248 113 902 175 5312 41 166 176 5376 25 336 1775440 43 170 178 5504 21 86 179 5568 43 174 180 5632 45 176 181 5696 45178 182 5760 161 120 183 5824 89 182 184 5888 323 184 185 5952 47 186186 6016 23 94 187 6080 47 190 188 6144 263 480

M is K in the foregoing table. By now, M can be obtained.

After M and N are obtained, spectral efficiency can be obtained.

A TBS in each modulation scheme with a code rate that falls within aninterval [0, 1] is selected. In AWGN, the TBS is used to emulate aminimum SINR required when a BLER is 10%. By now, the SINR can beobtained.

By using the SINR and the spectral efficiency, a curve of relationshipsis obtained.

Curves of relationships between spectral efficiency and SINRs indifferent modulation schemes, which are obtained by means of theforegoing emulation, may be shown in Table 3. Referring to FIG. 3, fourcurves from the bottom up correspond to QPSK, 16QAM, 64QAM, and 256QAMrespectively. SINR values and spectral efficiency values at anintersection of two curves are (4.5 dB, 1.45), (12.5 dB, 3.5), and(19.2, 5.5) respectively.

(2) According to the curve of relationships corresponding to eachmodulation scheme, a value of each item in the CQI corresponding to eachmodulation scheme is obtained.

A certain number of points may be selected for each modulation scheme.On the curve of relationships corresponding to the modulation scheme,the spectral efficiency corresponding to the selected points isobtained. The value of the obtained spectral efficiency is the value ofspectral efficiency in Table 3. The value of the spectral efficiency isdivided by the modulation order to obtain a code rate, and then the coderate is multiplied by 1024 to obtain the value of code rate×1024 inTable 3, where the modulation order of QPSK is 2, the modulation orderof 16QAM is 4, the modulation order of 64QAM is 6, and the modulationorder of 256QAM is 8.

The points selected in each of the modulation schemes meet the followingconditions:

(1) When the SINR is less than a set value, tale points selected in anequal-SINR manner; and, when the SINR is greater than or equal to theset value, the points are selected in an equal-spectral-efficiencymanner.

In this embodiment, the set value is 4.5 dB, and therefore, for the QPSKscheme, the points are selected in an equal-SINR manner; and, for 16QAM,64QAM, and 256QAM, the points are selected in anequal-spectral-efficiency manner. It can be understood that because Mhas a selection range, a point obtained in the equal-spectral-efficiencymanner or the equal-SINR manner s a point from which a value can beobtained and which is closest to the point obtained in the equal-SINRmanner or the equal-spectral-efficiency manner.

In addition, in this embodiment, to ensure coverage, the CQI table stillincludes the corresponding modulation scheme when the SINR is small.However, to avoid using excessive CQI indexes to denote the modulationscheme when the SINR is small, the number of the correspondingmodulation schemes when the SINR is small is reduced in this embodiment.For example, Table 1 is compared with Table 3 and it can be seen thatthe number of QPSK modulation schemes used in this embodiment is lessthan the number of QPSK modulation schemes used in the prior art.

(2) In a set range of an intersection of the curves of relationshipscorresponding to the two modulation schemes, a CQI index is selected,the modulation scheme corresponding to the selected CQI index is ahigher-order modulation scheme in the two modulation schemes, and adifference between the spectral efficiency corresponding to the selectedCQI index and maximum spectral efficiency in the other modulation schemein the two modulation schemes is less than a difference between spectralefficiency values corresponding any two CQI indexes in the higher-ordermodulation scheme.

The set range may be within a range of 0.5 dB near the intersection. Forexample, the SINR value at the intersection of QPSK and 16QAM is 4.5 dB,and therefore, CQI index needs to be set in a range of (4.5−0.5,4.5+0.5), and the modulation scheme corresponding to the index is thehigher-order modulation scheme. That is, the corresponding modulationscheme is 16QAM. A value of spectral efficiency and a value of a coderate are obtained according to a curve of relationships corresponding to16QAM.

Referring to Table 3, a difference between spectral efficiencycorresponding to a CQI whose index is 4 and spectral efficiencycorresponding to a CQI whose index is 3 is less than a differencebetween any two of spectral efficiency values corresponding to CQIswhose indexes are 4, 5, and 6.

After the CQI table is determined in the foregoing manner, the MCS tableincludes:

(1) all modulation schemes included in the CQI table;

for example, values corresponding to QPSK, 16QAM, 64QAM, and 256QAM inTable 3 are 3, 3, 5, and 4 respectively, and therefore, a modulationscheme in Table 4 corresponding to the 4 includes at least 3, 3, 5, and4 values; and

(2) values obtained by performing interpolation for the modulationschemes included in the CQI table.

For example, there are 3 points corresponding to QPSK, and 2 points areobtained after interpolation is performed on the 3 points. Theinterpolation may specifically be equal interval interpolation. Forexample, equal-SINR-interval interpolation is used for QPSK, andequal-spectral-efficiency-interval interpolation is used for 16QAM,64QAM, and 256QAM.

After the interpolation, the MCS table includes the modulation schemeitself and the values after the interpolation, in which at least valuescorrespond to QPSK. Similarly, in the MCS table, there are at least3+2=5 values corresponding to 16QAM, there are 5+4=9 valuescorresponding to 64QAM, and there are 4+3=7 values corresponding to256QAM.

Because there are 28 valid values in the MCS table, the number of valuesafter the interpolation is 5++9+7=26, and values corresponding to twoMSC indexes remain. The remaining values of the two MCS indexes may beobtained by performing extrapolation or by selecting a TBS that is thesame as that of another adjacent modulation scheme.

In a manner in which extrapolation is, used, for example, referring toTable 4, after extrapolation is performed for 16QAM and QPSK, an MCSindex corresponding to 16QAM is obtained; and, after extrapolation isperformed for 64QAM and 256QAM, an MCS index corresponding to 64QAM isobtained.

In a manner in which a same TBS is used, for example, referring to Table5, the TBS with an index of 5 and a modulation scheme of 16QAM is thesame as the TBS with an index of 4 and a modulation scheme of QPSK; andthe TBS with an index of 20 and a modulation scheme of 64QAM is the sameas the TBS with an index of 21 and a modulation scheme of 256QAM.

By means of the foregoing determining principles, a type of the secondset of tables may be obtained, such as Table 3 and Table 4, or Table 3and Table 5. It can be seen from the foregoing tables that the secondset of tables can support higher modulation schemes, and specificallycan further support 256QAM. For example, when spectral efficiency isapproximately 5.5, it can be learned from Table 3 that the usedmodulation scheme is 256QAM, but in the existing protocol, 64QAM isused. Therefore, this embodiment can support higher-order modulationschemes and improve system performance.

In addition, the number of CQI indexes in the CQI table in the secondset of tables is the same as that in the CQI table in the first set oftables. Likewise, the number of MCS indexes in the MCS table in thesecond set of tables is the same as that in the MCS table in the firstset of tables. Therefore, this embodiment is compatible with theexisting protocol. Specifically, for the MCS table, because 4 modulationschemes are supported in this embodiment, 4 bits are required in thereserved part of the MCS table. The reserved part may be an MCS indexnumber used for hybrid automatic repeat request (Hybrid Automatic RepeatRequest, HARQ) retransmission.

The number of indexes in the second set of tables used in the foregoingembodiment is the same as that in the existing first set of tables.Optionally, the present invention gives another embodiment. In thisembodiment, different from the existing CQI that occupies 4 bits, theCQI in this embodiment occupies 5 bits, and therefore, the number of CQIindexes is 32, but the existing number of CQI indexes is 16. In thiscase, the additional index entries may be used to denote 256QAM.

In a new CQI table, N index numbers are reserved for other signalingnotification, where N=Nmodu−1, and Nmodu is the number of supportedmodulation schemes.

In this case, a size of the MCS table may be the same as that in theprior art, but higher modulation schemes are supported.

in this embodiment, a higher-order modulation scheme can be supported byusing the second set of tables; and, with the QPSK modulation schemestill included, coverage is sufficiently considered. Compared with theprior art, this embodiment reduces values corresponding to QPSK, whichcan reduce waste of feedback overhead. By selecting a smaller differencebetween spectral efficiency values in two adjacent modulation schemes,transition between the two modulation schemes is more stable. Thecorresponding value is obtained for the higher-order modulation schemein an equal-spectral-efficiency manner, which can improve systemperformance smoothly.

FIG. 4 is a schematic structural diagram of an embodiment of aninformation transmission device according to the present invention. Thedevice may be a UE. The device includes a first sending module 41, afirst receiving module 42, and a second receiving module 43. The firstsending module 41 is configured to report a CQI value to an eNB; thefirst receiving module 42 is configured to receive an MCS value sent bythe eNB, where the MCS value is determined by the eNB according to theCQI value; and the second receiving module 43 is configured to receivePDSCH data according to the MCS value, where the CQI value and the MCSvalue are determined according to a second set of tables, where amodulation scheme supported by the second set of tables is higher than64QAM.

Optionally, referring to FIG. 5, the device may further include a secondsending module 51 and a third receiving module 52. The second sendingmodule 51 is configured to send control signaling to the eNB, where thecontrol signaling is used to indicate that the device supports thesecond set of tables; and the third receiving module 52 is configured toreceive control signaling sent by the eNB, where the control signalingis used to indicate use of the second set of tables.

Optionally, referring to FIG. 6, the device may further include a thirdsending module 61. The third sending module 61 is configured to: ifcontrol signaling that is sent by the eNB and used to indicate use of afirst set of tables is received, use the first set of tables to reportthe CQI value to the eNB so that the eNB determines the MCS valueaccording to the first set of tables.

Optionally, the second set of tables corresponding to the first sendingmodule and the first receiving module meets the following conditions:

some entries in the second set of tables are the same as those in thefirst set of tables;

the number of CQI indexes of a CQI table in the second set of tables isthe same as that in the first set of tables; and

the number of MCS indexes of an MCS table in the second set or tables isthe same as that in s first set of tables, and the MCS table in thesecond set of tables includes MCS index entries reserved for HARQretransmission of a modulation scheme higher than 64QAM.

Optional, the first sending module determines the CQI value by using theCQI table in the second set of tables, and spectral efficiency in theCQI table in the second set of tables meets the following conditions:

in any modulation scheme whose modulation order is higher than 2,differences between two adjacent spectral efficiency values areapproximately equal, where being approximately equal to b means that anabsolute value of a difference between a and b is less than a set value;and

a difference between spectral efficiency values that respectivecorrespond to two adjacent modulation schemes is less than a differencebetween any two adjacent spectral efficiency values in a singlemodulation scheme in the two modulation schemes.

Optional the MCS value received by the first receiving module isdetermined by using the MCS table in the second set of tables, and theMOS table in the second set of tables includes:

all modulation schemes included in the CQI table;

values obtained by performing interpolation for the modulation schemesincluded in the CQI table; and

values obtained by performing extrapolation for the modulation schemesincluded in the CQI table; or, values that have the same TBS as that ofthe modulation schemes included in the CQI table.

Further, the eNB may use the following manner to determine a type of thetable to be used:

if an RSRP or an RSRQ greater than a set value, determining to use thesecond set of tables; or

if CQI orders reported by the UE and received in a set time are higherthan a set order and data is continuously and correctly received,determining to use the second set of tables.

Further, the CQI table in the second set of tables in this embodimentmay be specifically shown in Table 3, and the MCS table in the secondset of tables may be specifically shown in Table 4 or Table 5.

In this embodiment, a higher-order modulation scheme can be supported byusing the second set of tables; and, with the QPSK modulation schemestill included, coverage is sufficiently considered. Compared with thepr for art, this embodiment reduces values corresponding to QPSK, whichcan reduce waste of feedback overhead. By selecting a smaller differencebetween spectral efficiency values in two adjacent modulation schemes,transition between the two modulation schemes is more stable. Thecorresponding value is obtained for the higher-order modulation schemein an equal-spectral-efficiency manner, which can improve systemperformance smoothly.

Persons of ordinary skill in the art may understand that all or a partof the steps of the method embodiments may be implemented by a programinstructing relevant hardware. The program may be stored in a computerreadable storage medium. When the program runs, the steps of the methodembodiments are performed. The foregoing storage medium includes: anymedium that can store program code, such as a ROM, a RAM, a magneticdisk, or an optical disc.

Finally, it should be noted that the foregoing embodiments are merelyintended for describing the technical solutions of the presentinvention, other than limiting the present invention. Although thepresent invention is described in detail with reference to the foregoingembodiments, persons of ordinary skill in the art should understand thatthey may still make modifications to the technical solutions describedin the foregoing embodiments, or make equivalent substitutions to someor all the technical features thereof, without departing from the spiritand scope of the technical solutions of the embodiments of the presentinvention.

What is claimed is:
 1. An information transmission method, comprising:sending, by a user equipment (UE), control signaling to an eNodeB (eNB),wherein the sent control signaling is used to indicate that the UEsupports a second set of tables including a second modulation and codingscheme (MCS) table and a second channel quality indicator (CQI) table,wherein a modulation scheme that can be supported by the second set oftables is 256QAM, wherein the UE also supports a first set of tablesincluding a first MCS table different from the second MCS table and afirst CQI table different from the second CQI table; receiving, by theUE, control signaling sent by the eNB, wherein the received controlsignaling is used to indicate use of the second set of tables;determining, by the UE, a CQI value by using the second CQI table;reporting, by the UE, the CQI value to the eNB, wherein the CQI value isfor the eNB to determine an MCS value according to the CQI value;receiving, by the UE, the MCS value sent by the eNB; and receiving, bythe UE, physical downlink shared channel (PDSCH) data according to theMCS value.